Rotor for synchronous electric motors



March 16, 1948. J. ROSE 2,437,922

ROTOR FOR SYNCHRONOUS ELECTRIC MOTORS Filed April 15, 1947 -M I \NVENTORIf $4 Patented Mar. 16, 1948 UNITED STATES PATENT Jay Rose, New York, N.Y. Application April 15, 1947, Serial No. 741,615

1 Claim.

This invention relates to improvements in synchronous electric motorsespecially well adapted for operating timing mechanisms. The object ofthe invention is to provide certain improvements in the manufacture andassembly oi. the rotor elements whereby savings in labor and materialmay be effected and a more eflicient rotor element provided. Theinvention is embodied in a synchronous electric motor arranged andconstructed as hereinafter set forth and as illustrated in theaccompanying drawing in which Fig. l is a face view of a motor embodyingthe invention.

Fig. 2 is a side view.

Fig. 3 is a view of the outside copper disk of the rotor which serves tohold the rotor laminae together.

Fig. i is a view of one of the laminae.

Fig. 5 is a schematic view illustrating the particular manner ofassembling the rotor elements and holding them together.

Fig. 6 is a detail view in perspective of a part of the holding meansfor the laminae.

Fig. 7 shows a modification.

The motor comprises the stator l, 2 having the coil 3 and provided withcopper laminae 4, l forming the usual Sheridan bridge. The two legs ofthe stator are held together by any suitable framework such as indicatedat 6. l indicates bolt holes for mounting the motor on the framework orthe mechanism to which the motor is to be attached, such framework notbeing shown. The rotor 8 is mounted upon and drives a shaft 93 which inturn will drive such mechanism. The stator is constructed of laminae asshown.

The rotor 3 consists of as many laminae as may be required for the workto be performed. Each lamina is in the form of a disk or wheel, Fig. a,having a rim i5, spokes l6 and'a hub ll. The rim is formed with aplurality of recesses ill with teeth therebetween. The recesses formslots axially across the laminae when they are assembled.

The laminae are held together by two outside copper disks or rings suchas shown in Fig. 3. The shape and arrangement of the copper rings form afeature of this invention. .Each ring comprises a circular rim havingradial arms 2| extending therefrom. Each arm terminates in a holdingtooth 22 positioned at right anglesto the arm. At the base of the armthere is an abutment 23.

In assembling the rotor a suitable number of iron laminae l5 areassembled side by side as 2 shown in Fig. 5 with the slots l8 inregistry. Then one copper ring 20 is placed on one side of the assembledlaminae and the other copper ring on the other side. The teeth 22 of theone ring point in a direction opposite to that of the teeth in the otherring. As shown in Fig. 5 one copper ring 30 is placed on one side of thelaminae and the arms 3! (N in Fig. 3) are bent in over and around theedges of the laminae and pressed down into the slot is. This one bendingof the arm automatically places the tooth 32 of the arm (22 in Fig. 3)on the outside of the laminae on the opposite side so that the teeth ofthe laminae are clamped together between the said teeth 32 and theabutments 33 (23 in Fig. 3) and no further bending operation isrequired. The length of the arms 2E (35) between the tooth 22 (32) andthe abutment 23 (33) is made slightly less than the thickness of theassembled laminae so that when the arm is bent down into the slot is thetooth oi the arm will snap down over the opposite edge oi. the assembledlaminae and thus clamp them together as will be understood.

Then the second copper ring is placed on the opposite side of thelaminae and its arms are bent to occupy the alternate unoccupied slotsit. In Fig. 5 the second copper ring is marked 4i], its arms it, itsteeth 12 and its abutments ii to distinguish from the first copper ring.

The arms or the copper rings are bent in over the laminae occupyingalternate slots l8 and the teeth on the laminae are clamped between theteeth and the abutments on the copper rings as shown in 5. Only onebending of the copper ring teeth is required and a better grip upon thelaminae is obtained than when bending the ends 02 the-arms a second timearound the laminae such as is provided in some prior disclosures. Astill further advantage is obtained in that there is a continuous ringof copper along the circular rim of the rotor as shown at the bottom ofFig. 5 to provide for a continuous path for the how of the current and amore even ilow.

In the modification shown in Fig. 7 the copper arms 50 have an abutment5! on each side at the base of the arm and the teeth 52 at the free endof the arm extends across the arm. The teeth on the laminae are clampedbetween the teeth and the abutments on adjacent arms.

I claim:

A rotor for a synchronous electric motor as described comprising aplurality of circular iron laminae and two outer identical copper rings,one on each side of the assembled laminae, said laminae having recessesin their rims forming spaced slots in the circumference of the assembledlaminae axially thereof. each copper ring having outwardly extendingradial arms including a tooth portion at the free end of each armextending to one side of the arm and abutments formed in the rimintegral with said arms at the bases thereof, said tooth portions andsaid abutments being radially aiined on said rings, the tooth portionson onering extending in a direca tion pposite to the tooth portions onthe other ring, the arms of one of the copper rings being bent in onedirection around the edges of the assembled laminae on the one sidethereof and embedded in alternate slots in the laminae, the arms or theother copper ring being bent in the opposite direction around the edgesof the assembled laminae on the other side thereof and likewise embeddedin alternate slots in the assembled laminae, the tooth portions on eachof said rings engaging the laminae on the opposite side incircumferentially alternate positions to clamp said laminae between saidtooth portions and the said abutments.

JAY ROSE.

